JPH0670538B2 - Absorption refrigerator control method - Google Patents

Description

Description: (a) Field of Industrial Application The present invention relates to a method for controlling an absorption chiller in which hot water flowing out from an engine jacket, that is, engine cooling water is used as a driving heat source.

(B) Prior art Absorption refrigerators that use engine cooling water as a driving heat source (hereinafter referred to as "absorption refrigerators of this type") include
It has been known for a long time as described in Japanese Patent No. 7799. However, in this type of absorption refrigerator that has been known for a long time, the flow rate and temperature of the engine cooling water (hereinafter referred to as engine cooling water) supplied to the generator are adjusted so as to match the load on the cooling side, for example. Since it is not adjusted to, it was not practical because the cooling was insufficient or excessive.

Therefore, for example, as described in Japanese Utility Model Application Laid-Open No. 57-5677, a flow control valve for bypassing a generator is provided in a circuit of engine cooling water that connects a jacket of an engine and a generator of an absorption refrigerator. A means for providing a bypass passage and adjusting the flow rate of engine cooling water circulating through the generator according to the load (refrigeration load) on the cooling side has been put into practical use in the past.

According to this conventional means, there is an advantage that the refrigerating capacity of this type of absorption refrigerator can be adjusted to almost match the refrigerating load, but on the other hand, the engine cooling returning to the jacket with the change of the refrigerating load or the load on the engine side. There is a drawback that the temperature of water changes and the engine overheats or becomes too cold. Therefore, in this conventional means, in order to keep the engine cooling water to be returned to the jacket at a predetermined temperature, it is necessary to provide a radiator and a heater in the circuit of the engine cooling water, and the heat radiation amount in these devices. And heating amount must be controlled simultaneously or separately.

As described above, the conventional means have the drawbacks that the whole system becomes complicated and expensive, and the control becomes complicated and complicated.

(C) Object of the present invention The present invention provides a control method capable of preventing overheating or overcooling of an engine with simple control and exhibiting a refrigerating capacity almost corresponding to a refrigerating load in this type of absorption refrigerator. It is a thing.

(D) Structure of the invention The present invention relates to an absorption refrigerating machine of this type, in which the absorption liquid pipe from the absorber to the generator via the solution heat exchanger or the absorption from the generator to the absorber via the solution heat exchanger is absorbed. A bypass pipe that bypasses the solution heat exchanger via the three-way valve is provided in the liquid pipe, and the opening of the absorption liquid pipe and the bypass pipe of the three-way valve are controlled according to the refrigeration load. When the refrigeration load is 100%, the opening of the three-way valve on the absorbent conduit side is set to 100%, and the opening of the bypass conduit is controlled to 0%. The opening degree of the bypass pipe side is increased and the refrigeration load is zero.
To provide a control method for controlling the opening of the three-way valve on the side of the absorbing liquid line to 0% and the opening on the side of the bypass line to 100%.

In an absorption refrigerator that controls a three-way valve as in the control method of the present invention, for example, when the refrigeration load is reduced, a rare absorption liquid whose temperature is lowered according to the decrease in the load is introduced into the generator. , It is possible to suppress the concentration of the absorbing liquid in the generator by increasing the calorific consumption (sensible heat consumption) for raising the temperature of the rare absorbing liquid to the boiling temperature. It is possible to suppress the above, and to exert the refrigerating capacity almost commensurate with the reduced load. On the other hand, when the refrigeration load is reduced, the heat of the engine cooling water (warm water) supplied to the generator is consumed to raise the temperature of the rare absorption liquid that has flowed into the generator at a low temperature, and the engine cooling water flowing out of the generator is consumed. Even when the temperature drops, especially when the refrigeration load becomes low or when the refrigeration load disappears, most or all of the absorbing liquid flowing from the absorber to the generator flows to the bypass pipe line, and It is possible to suppress the amount of heat exchange slightly or to eliminate it altogether, and the rare absorption liquid that radiates heat to the cooling water in the absorber flows to the generator without being heated in the solution heat exchanger,
The temperature of the rare absorption liquid flowing into the generator can be further lowered, and the overheating of the engine side can be reliably prevented even when the refrigeration load becomes small or when the refrigeration load disappears.

(E) Embodiment FIG. 1 is a schematic structural explanatory view showing an embodiment of a control device for an absorption refrigerator of this kind according to the present invention, in which (1) is a generator, (2) is a condenser, and ( 3) is an evaporator, (4) is an absorber, (5) is a solution heat exchanger, (6) is a pump for a refrigerant liquid, (7) is a pump for an absorbent liquid, and the refrigerant vapor flows through these devices. Pipes (8), (9), pipes (1) through which the refrigerant liquid flows
0), refrigerant liquid reflux pipes (11), (12), dilute absorption liquid flow pipes (13), (14), concentrated absorption liquid flow down pipe (15)
Connected by the same refrigerant (water) as the conventional absorption refrigerator
It also constitutes a circulation path for the absorbing liquid (lithium bromide aqueous solution).

(16) is a heater built in the generator (1), (17) is a cooler built in the condenser (2), (18) is a water cooler built in the evaporator (3), and (19) is absorption Coolers (20) and (21) built in the device (4) are pipes (22) and (22) where engine cooling water (warm water) flows connected to a heater (16) and an engine jacket (not shown). Reference numeral 23) is a cooling water flow pipe connected to the cooler (17), and (24) and (25) are cooling water flow pipes connected to the water cooler (18) and the cooling load side heat exchanger (not shown). , (26), (27) are cooling water flow pipes connected to the cooler (19), (28) is a sprayer of rare absorbent, (29) is a sprayer of concentrated absorbent, (30). Is a sprayer of refrigerant liquid, (31),
(32) is a refrigerant liquid reservoir, and (33) and (34) are solution reservoirs.

Reference numeral (35) is a bypass pipe provided in the pipe (14) via a three-way valve (V), which allows the dilute absorption liquid to bypass the solution heat exchanger (5). (S) is a detector for detecting the temperature of cold water flowing out from the cold water cooler (18). Then, for example, when the cooling load decreases and the temperature of the chilled water flowing out from the chiller (18) begins to drop, the bypass pipe (35) side opening of the three-way valve (V) is changed by the signal of the detector (S). The temperature of the rare absorbent flowing into the generator (1) is lowered by decreasing the inlet side opening of the pipe (14) and decreasing the exchange amount of the rare absorbent in the solution heat exchanger (5) while increasing the temperature. I am trying. When the temperature of the rare absorbent flowing into the generator (1) becomes low, the amount of heat (sensible heat) required to raise the rare absorbent to the boiling temperature in the generator (1) increases. Therefore, of the amount of heat exchanged between the absorbing liquid and the engine cooling water (warm water) in the generator (1), the amount of heat (latent heat amount) consumed for concentrating the absorbing liquid decreases as the amount of sensible heat increases, and is generated. The degree of concentration of the absorption liquid in the vessel (1) decreases. On the other hand, the amount of heat taken by the engine cooling water (warm water) by the absorbing liquid in the generator (1) is the same as that before the cooling load (refrigeration load) is decreased because the sensible heat amount increases with the decrease of the latent heat amount. The same or slightly more. As a result, the temperature of the engine cooling water returned from the generator (1) to the engine jacket (not shown) side is the cooling load (refrigeration load).
It will be about the same as or lower than before. Therefore, even when the refrigeration load is reduced, overheating of the engine can be prevented. Further, as the degree of concentration of the absorption liquid in the generator (1) decreases, the concentration of the absorption liquid circulating in the machine also decreases, and the refrigerant absorption capacity of the absorption liquid sprinkled in the absorber (4) decreases. As the refrigeration load decreases, the refrigeration capacity also decreases.

FIG. 2 is a Duhring diagram showing an example of the operation of an absorption refrigerating machine of this type provided with the control device of the present invention. In the figure, the A → B → C → D → A cycle represented by the solid line is a refrigerating load. Is 100
% Shows the rated cycle of the absorption liquid, and the refrigerating load is shown in the A '→ B' → C '→ D' → A 'cycle indicated by the dotted line.
The cycle of the absorbing solution when it is reduced to 50% (hereinafter referred to as 50% cycle) is shown.

During the rated cycle, the bypass pipe (35) of the three-way valve (V)
The side opening is 0% (fully closed) and the inlet side opening of the pipe (14) is 100% (fully open) to allow a dilute absorption liquid of about 73 ° C to flow into the generator (1), and the condenser. (2) The internal pressure is operated at about 60 mmHg, and the engine (1) is heated by supplying the engine cooling water at about 90 ° C to the heater (16). Then, during the rated cycle, the cold water that has flowed into the water cooler (18) at approximately 18 ° C flows out from the water cooler (18) at approximately 13 ° C, and the refrigerating capacity to be exhibited is approximately 3024 kcal / hr. The temperature of the engine cooling water flowing out of (16) is maintained at about 85 ° C, and the amount of heat absorbed by the absorbing liquid of the engine cooling water is about 4320 kcal /
hr (1296 kcal / hr for sensible heat, about 3024 kcal for latent heat)
/ Hr).

Next, at the 50% cycle, the bypass pipe (35) side opening of the three-way valve (V) is set to 50% by the signal of the detector (S), and the pipe (14) inlet side opening is set to 50%. Allow the dilute absorption liquid at 69 ℃ to flow into the generator (1), and reduce the internal pressure of the condenser (2) to approx.
It is operated at 60 mmHg and is operating while supplying engine cooling water of about 90 ° C to the heater (16). And, at the time of 50% cycle, the cold water that has flowed into the water cooler (18) at about 15.5 ° C flows out from the water cooler (18) at about 13 ° C, and the refrigerating capacity to be exerted is about 1512 kcal / hr, and the heating The temperature of the engine cooling water flowing out of the vessel (16) is maintained at about 85 ° C, and the amount of heat absorbed by the absorption liquid of the engine cooling water is about 4320 kcal / hr.
(Sensible heat amount is about 2808 kcal / hr Latent heat amount is about 1512 kcal / h
r).

In this way, when the refrigeration load changes, the opening of the three-way valve (V) is controlled by the signal of the detector (S) to adjust the temperature of the rare absorbent flowing into the generator (1). Adjust the refrigeration capacity to almost match the changed load, and keep the temperature of the engine cooling water returned to the engine side within a predetermined range (for example, in the range of about 85 ℃ -80 ℃) to prevent overheating or overcooling on the engine side. It is preventing.

FIG. 3 is a diagram showing an example of controlling the three-way valve (V) opening with respect to the refrigeration load. In the figure, the dotted line represents the bypass pipe (35) side opening of the three-way valve (V), and the solid line represents the three-way valve ( V) tube (14)
It represents the opening degree on the inlet side. As shown in FIG. 3, the opening of the three-way valve (V) on the side of the bypass pipe (35) decreases as the refrigerating load increases, and becomes zero when the refrigerating load is 100%. All flow into the bypass pipe (35). Further, the opening degree of the three-way valve (V) on the inlet side of the pipe (14) increases as the refrigeration load increases, and becomes 100% when the refrigeration load is 100%.

In FIG. 1, instead of providing the bypass pipe (35) on the pipe (14), the bypass pipe (35) is connected to the pipe (15) via the three-way valve (V ′) as shown by the two-dot chain line in the figure. It is also possible to adjust the temperature of the rare absorbent flowing into the generator (1) by providing ′) and adjusting the amount of heat exchanged between the rare absorbent and the concentrated absorbent. Also, although not shown, the pipe (15)
Alternatively, the bypass pipe (35 ') may be provided with an auxiliary cooler so that the temperature of the concentrated absorbing solution sprayed to the absorber (4) may be adjusted to be substantially constant. When the temperature of the concentrated absorbent is kept substantially constant, the opening control of the three-way valve (V) with respect to the refrigeration load is different from that shown in FIG. 3 (not shown).

(F) Effects of the Invention As described above, in the present invention, in this type of absorption refrigerator, a bypass pipe is provided in the pipe of the absorbing liquid via the control valve, and the opening of the control valve is set to the refrigeration load (for example, It is controlled according to the cooling load) and the temperature of the rare absorption liquid flowing into the generator is adjusted, so the sensible heat exchange amount between the engine cooling water and the absorption liquid in the generator can be adjusted. .

Therefore, in the method for controlling an absorption refrigerator according to the present invention, for example, when the refrigeration load is reduced, the sensible heat exchange amount of the absorbing liquid in the generator can be increased to reduce the latent heat exchange amount of the absorbing liquid. It is possible to suppress the concentration of the absorption liquid. As a result, the refrigerant absorption capacity of the absorbing liquid in the absorber is lowered, and the refrigeration capacity almost commensurate with the reduced refrigeration load can be exhibited. In addition, the amount of heat absorbed by the absorption liquid of the engine cooling water (hot water flowing into the heater of the generator from the engine jacket side) increases the sensible heat exchange amount while decreasing the latent heat exchange amount. It does not change much before it decreased. As a result, the temperature of the engine cooling water returned from the heater of the generator to the jacket side of the engine does not become too high. Especially when the refrigeration load becomes small or when the refrigeration load disappears, most or all of the absorption liquid flowing from the absorber to the generator flows to the bypass line, increasing the temperature of the absorption liquid in the solution heat exchanger. Of course, the absorption liquid flows to the generator without being heated by the solution heat exchanger when the refrigeration load is removed, further lowering the temperature of the rare absorption liquid flowing into the generator. Therefore, even when the refrigeration load becomes small or when the refrigeration load disappears, overheating on the engine side can be reliably prevented.

Conversely, when the refrigeration load increases again, the sensible heat exchange amount of the absorbing liquid can be reduced and the latent heat exchange amount can be increased by adjusting the temperature of the rare absorbing liquid flowing into the generator to be high. Therefore, it is possible to prevent the engine from overcooling by preventing the temperature of the engine cooling water returned to the jacket side of the engine from being excessively lowered, and to accelerate the concentration of the absorbing liquid to achieve a refrigerating capacity that almost matches the increased refrigerating load. Can be demonstrated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration explanatory view showing an embodiment of an absorption refrigerating machine of this type controlled based on the control method of the present invention, and FIG.
FIG. 3 is a Duhring diagram showing an example of the operation of an absorption refrigerator based on the control method of the present invention, and FIG. 3 is a diagram showing the opening of a three-way valve with respect to the refrigeration load using the control method of the present invention. Is. (1) ... Generator, (2) ... Condenser, (3) ... Evaporator,
(4) ... Absorber, (5) ... Solution heat exchanger, (6) (7)
… Pump, (13) (14) (15)… Pipe, (16)… Heater,
(18)… Chiller, (20) (21) (24) (25)… Pipe, (3
5) (35 ') ... bypass pipe, (S) ... detector, (V)
(V ') ... 3-way valve.

Claims (1)

[Claims] 1. An absorption chiller in which hot water flowing out from an engine jacket is used to heat a generator and then returned to the jacket side of the engine. A bypass line that bypasses the solution heat exchanger via a three-way valve is provided in the absorption line from the line or generator to the absorber via the solution heat exchanger, and the absorption liquid of the three-way valve is adjusted depending on the refrigeration load. By controlling the opening degree on the pipeline side and the opening degree on the bypass pipe side, when the refrigeration load is 100%, the opening degree on the absorption liquid pipeline side of the three-way valve is set to 100% and the opening degree on the bypass pipeline side is set to 0%. When the refrigeration load is 0%, the opening of the three-way valve on the side of the absorption liquid conduit is decreased and the opening of the bypass pipe is increased along with the decrease of the refrigeration load. Set the opening to 0% and set the opening on the bypass line side to 1 A method for controlling an absorption chiller, which is characterized by controlling at 00%.